/*
 * Copyright (C) 2021 Huawei Device Co., Ltd.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "l2cap_crc.h"

#define G_CRCTABLENUM 256
static const uint16_t G_CRCTABLE[G_CRCTABLENUM] = {
    0x0000, 0xc0c1,
    0xc181, 0x0140,
    0xc301, 0x03c0,
    0x0280, 0xc241,
    0xc601, 0x06c0,
    0x0780, 0xc741,
    0x0500, 0xc5c1,
    0xc481, 0x0440,
    0xcc01, 0x0cc0,
    0x0d80, 0xcd41,
    0x0f00, 0xcfc1,
    0xce81, 0x0e40,
    0x0a00, 0xcac1,
    0xcb81, 0x0b40,
    0xc901, 0x09c0,
    0x0880, 0xc841,
    0xd801, 0x18c0,
    0x1980, 0xd941,
    0x1b00, 0xdbc1,
    0xda81, 0x1a40,
    0x1e00, 0xdec1,
    0xdf81, 0x1f40,
    0xdd01, 0x1dc0,
    0x1c80, 0xdc41,
    0x1400, 0xd4c1,
    0xd581, 0x1540,
    0xd701, 0x17c0,
    0x1680, 0xd641,
    0xd201, 0x12c0,
    0x1380, 0xd341,
    0x1100, 0xd1c1,
    0xd081, 0x1040,
    0xf001, 0x30c0,
    0x3180, 0xf141,
    0x3300, 0xf3c1,
    0xf281, 0x3240,
    0x3600, 0xf6c1,
    0xf781, 0x3740,
    0xf501, 0x35c0,
    0x3480, 0xf441,
    0x3c00, 0xfcc1,
    0xfd81, 0x3d40,
    0xff01, 0x3fc0,
    0x3e80, 0xfe41,
    0xfa01, 0x3ac0,
    0x3b80, 0xfb41,
    0x3900, 0xf9c1,
    0xf881, 0x3840,
    0x2800, 0xe8c1,
    0xe981, 0x2940,
    0xeb01, 0x2bc0,
    0x2a80, 0xea41,
    0xee01, 0x2ec0,
    0x2f80, 0xef41,
    0x2d00, 0xedc1,
    0xec81, 0x2c40,
    0xe401, 0x24c0,
    0x2580, 0xe541,
    0x2700, 0xe7c1,
    0xe681, 0x2640,
    0x2200, 0xe2c1,
    0xe381, 0x2340,
    0xe101, 0x21c0,
    0x2080, 0xe041,
    0xa001, 0x60c0,
    0x6180, 0xa141,
    0x6300, 0xa3c1,
    0xa281, 0x6240,
    0x6600, 0xa6c1,
    0xa781, 0x6740,
    0xa501, 0x65c0,
    0x6480, 0xa441,
    0x6c00, 0xacc1,
    0xad81, 0x6d40,
    0xaf01, 0x6fc0,
    0x6e80, 0xae41,
    0xaa01, 0x6ac0,
    0x6b80, 0xab41,
    0x6900, 0xa9c1,
    0xa881, 0x6840,
    0x7800, 0xb8c1,
    0xb981, 0x7940,
    0xbb01, 0x7bc0,
    0x7a80, 0xba41,
    0xbe01, 0x7ec0,
    0x7f80, 0xbf41,
    0x7d00, 0xbdc1,
    0xbc81, 0x7c40,
    0xb401, 0x74c0,
    0x7580, 0xb541,
    0x7700, 0xb7c1,
    0xb681, 0x7640,
    0x7200, 0xb2c1,
    0xb381, 0x7340,
    0xb101, 0x71c0,
    0x7080, 0xb041,
    0x5000, 0x90c1,
    0x9181, 0x5140,
    0x9301, 0x53c0,
    0x5280, 0x9241,
    0x9601, 0x56c0,
    0x5780, 0x9741,
    0x5500, 0x95c1,
    0x9481, 0x5440,
    0x9c01, 0x5cc0,
    0x5d80, 0x9d41,
    0x5f00, 0x9fc1,
    0x9e81, 0x5e40,
    0x5a00, 0x9ac1,
    0x9b81, 0x5b40,
    0x9901, 0x59c0,
    0x5880, 0x9841,
    0x8801, 0x48c0,
    0x4980, 0x8941,
    0x4b00, 0x8bc1,
    0x8a81, 0x4a40,
    0x4e00, 0x8ec1,
    0x8f81, 0x4f40,
    0x8d01, 0x4dc0,
    0x4c80, 0x8c41,
    0x4400, 0x84c1,
    0x8581, 0x4540,
    0x8701, 0x47c0,
    0x4680, 0x8641,
    0x8201, 0x42c0,
    0x4380, 0x8341,
    0x4100, 0x81c1,
    0x8081, 0x4040,
};

uint16_t CalCrc16WithPrev(uint8_t data, uint16_t preCrc)
{
    return ((preCrc >> 0x08) & 0x00ff) ^ G_CRCTABLE[(uint8_t)(preCrc & 0x00ff) ^ data];
}